Localization systems and methods using communication protocols with open channels and secure communication connections

ABSTRACT

Localization systems and methods are provided and include a first sensor that wirelessly communicates with a portable device using a secure communication connection during first and third time periods and second sensors that transmit broadcast signals over an open advertising communication channel during a second time period between the first and third time periods. The second sensors transmit the broadcast signals based on timing information determined by a control module that also communicates the timing information to the portable device using the secure communication connection. The portable device establishes scanning windows for receiving the broadcast signals based on the timing information and receives first signal information about first signals transmitted over the secure communication connection and second signal information about the broadcast signals transmitted by the second sensors. The control module determines a current location of the portable device based on the first signal information and the second signal information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/123,052, filed Sep. 6, 2018, which application claims the benefit ofU.S. Provisional Application No. 62/560,377, filed on Sep. 19, 2017. Theentire disclosures of the above applications are incorporated herein byreference.

FIELD

The present disclosure relates to localization systems and methods and,more particularly, to localization systems and methods usingcommunication protocols with open and secure connection channels.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

PEPS systems allow a vehicle to locate a key associated with thevehicle, such as a wireless key fob carried by a user of the vehicle.Traditionally, PEPS systems allow anyone in possession of a key fob thathas been previously paired with a vehicle's central PEPS electroniccontrol unit (ECU) to access the vehicle by simply grabbing the doorhandle and to start the vehicle with a push of a button. In response toa button push, the central PEPS ECU authenticates the key fob todetermine if the key fob is authorized to access the vehicle and usesthe signal strength indicated by a plurality of vehicle antennas toestimate the location of the key fob. If the key fob can beauthenticated and is located within an authorizing zone, the vehicle'sfunction is made available to the user, i.e. the vehicle doors areunlocked and/or the vehicle is started.

Traditional PEPS systems use proprietary grade radio protocols using lowfrequency (LF) signals of approximately 125 kHz. LF was selected forearly PEPS systems because the wave propagation would allow forrelatively accurate estimation of range and location by using signalstrength within the typical target activation range of 2 meters. The LFcommunication systems used with traditional PEPS systems, however, usefixed frequencies for communication and do not implement any frequencyhopping scheme or any encryption of communication packets.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

A system is provided and includes a first sensor configured to performwireless communication with a portable device using a communicationprotocol that allows for communication over at least one openadvertising communication channel and that allows for communicationusing a secure communication connection, the first sensor beingconfigured to communicate with the portable device using the securecommunication connection during a first time period. The system alsoincludes at least one second sensor configured to perform wirelesscommunication with the portable device by transmitting or receiving atleast one broadcast signal over the at least one open advertisingcommunication channel during a second time period. The system alsoincludes a control module configured to receive first signal informationabout first signals transmitted or received by the first sensor duringthe first time period and second signal information about second signalstransmitted or received by the at least one second sensor during thesecond time period and to determine a location of the portable devicebased on the first signal information and the second signal information.The first signal information and the second signal information includesat least one of received signal strength indicator information, angle ofarrival information, and time difference of arrival information.

In other features, the first sensor and the at least one second sensorare installed in a vehicle and the control module is further configuredto perform a vehicle function including at least one of unlocking a doorof the vehicle, unlocking a trunk of the vehicle, and allowing thevehicle to be started based on the location of the portable device.

In other features, the first sensor is configured to communicate withthe portable device using the secure communication connection byperforming frequency hopping spread spectrum communication.

A method is provided an includes performing, with a first sensor,wireless communication with a portable device using a communicationprotocol that allows for communication over at least one openadvertising communication channel and that allows for communicationusing a secure communication connection, the first sensor performing thewireless communication with the portable device using the securecommunication connection during a first time period. The method alsoincludes performing, with at least one second sensor, wirelesscommunication with the portable device by transmitting or receiving atleast one broadcast signal over the at least one open advertisingcommunication channel during a second time period. The method alsoincludes receiving, with a control module, first signal informationabout first signals transmitted or received by the first sensor duringthe first time period and second signal information about second signalstransmitted or received by the at least one second sensor during thesecond time period. The method also includes determining, with thecontrol module, a location of the portable device based on the firstsignal information and the second signal information. The first signalinformation and the second signal information includes at least one ofreceived signal strength indicator information, angle of arrivalinformation, and time difference of arrival information.

In other features, the first sensor and the at least one second sensorare installed in a vehicle, the method further comprising performing avehicle function including at least one of unlocking a door of thevehicle, unlocking a trunk of the vehicle, and allowing the vehicle tobe started based on the location of the portable device.

In other features, the first sensor performs communication with theportable device using the secure communication connection by performingfrequency hopping spread spectrum communication.

Another system is provided and includes a plurality of sensorsconfigured to perform wireless communication with a portable deviceusing a communication protocol that allows for communication over atleast one open advertising channel and that allows for communicatingusing a secure communication connection, the plurality of sensors beingconfigured to communicate with the portable device by transmitting orreceiving at least one broadcast signal over the at least one openadvertising communication channel, the plurality of sensors and theportable device being configured to synchronize at least one transmittime to transmit the at least one broadcast signal with at least onescanning window to receive the at least one broadcast signal. A controlmodule is configured to receive signal information about the at leastone broadcast signal transmitted or received by the plurality of sensorsand to determine a location of the portable device based on the signalinformation. The signal information includes at least one of receivedsignal strength indicator information, angle of arrival information, andtime difference of arrival information.

In other features, the plurality of sensors are installed in a vehicleand the control module is further configured to perform a vehiclefunction including at least one of unlocking a door of the vehicle,unlocking a trunk of the vehicle, and allowing the vehicle to be startedbased on the location of the portable device.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 illustrates a subject vehicle with a localization systemaccording to the present disclosure.

FIG. 2 illustrates a block diagram for a localization system accordingto the present disclosure.

FIG. 3 illustrates a block diagram for a sensor of a localization systemaccording to the present disclosure.

FIG. 4 illustrates a timing diagram for communication between a portabledevice and sensors according to an implementation of the presentdisclosure.

FIG. 5 illustrates another timing diagram for communication between aportable device and sensors according to another implementation of thepresent disclosure.

FIG. 6 illustrates a portable device and sensors according to anotherimplementation of the present disclosure.

FIG. 7 illustrates another timing diagram for communication between aportable device and sensors according to another implementation of thepresent disclosure.

FIG. 8 illustrates another timing diagram for communication between aportable device and sensors according to another implementation of thepresent disclosure.

FIG. 9 illustrates another timing diagram for communication between aportable device and sensors according to another implementation of thepresent disclosure.

FIG. 10 illustrates another timing diagram for communication between aportable device and sensors according to another implementation of thepresent disclosure.

FIG. 11 illustrates another timing diagram for communication between aportable device and sensors according to another implementation of thepresent disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

The present disclosure relates to systems, methods, and architecture toimplement a localization system using a consumer grade wireless protocolthat employs both open communication channels and secure communicationconnections. For example, the open communication channels can be used tobroadcast and receive advertising packets between two communicationdevices, such as a portable device and one or more sensors, such asvehicle sensors. The advertising packets are generally broadcast on theopen communication channels such that any communication device within acommunication range of the broadcasting communication device can receivethe advertising packets without the need for particular communicationinformation, such as information regarding the timing, encryption,decoding, etc., of the communication packets. The secure connectioncommunication channels can be used for secure communication between twocommunication device, such as a portable device and one or more sensors,such as vehicle sensors.

Communication devices can communicate using a secure connection by usingparticular communication information, such as information regarding thetiming, encryption, decoding, etc., of the communication packets, thatis known by the communicating devices. In this way, it is more difficultfor a third-party to eavesdrop or intercept on packets sent over thesecure communication connection between the communication devices. Forexample, communication protocols that utilize secure communicationconnections can use using frequency hopping spread spectrum (FHSS)communication, direct-sequence spread spectrum (DSSS) communication, ororthogonal frequency-division multiplexing (OFDM) communication duringcommunication over the secure communication connection. For example, theBluetooth Low Energy (BLE) communication protocol uses FHSScommunication during communication over the secure communicationconnection. For further example, the Wi-Fi and Wi-Fi directcommunication protocol uses DSSS and/or OFDM communication duringcommunication over the secure communication connection. Additionally oralternatively, the communication devices can use encryption forcommunication packets sent over the secure communication connection.

In accordance with the present teachings, communication protocols usingboth open and secure connection communication channels can be used forlocalization systems such as a PEPS system. In such case, acommunication protocol using both open and secure connectioncommunication channels can be used for communication between a vehicle,including sensors of a vehicle, and a portable device. The portabledevice, for example, can be a key fob, a smartphone, a tablet, awearable computing device (such as a smartwatch, a bracelet, a necklace,a ring, etc.), or any other suitable computing device configured forcommunication with a PEPS system using a communication protocol withboth open and secure connection communication channels. The wirelessprotocols also allow for limited unencrypted communication over openadvertising channels without using secure communication channels, butalso allow for communication over secure communication channels usingspread spectrum communication techniques, such as FHSS, DSSS, and/orOFDM. Communication between two communication devices using spreadspectrum techniques, such as FHSS, DSSS, and/or OFDM, increasessecurity, increases privacy, reduces power usage, and increasesreliability of the communication between the two devices. For example,communication over secure communication channels make it difficult forunauthorized devices to know the channel, timing, and/or decodinginformation to receive the next communication packet(s) between the twodevices. This feature makes it difficult for unauthorized devices to spyon the communication between a portable device and a PEPS system of thevehicle using secure communication channels.

With reference to FIGS. 1 and 2, a PEPS system 1 is provided within avehicle 5 and includes a PEPS control module 8 and a plurality ofsensors 10A to 10F, collectively referred to as 10. The PEPS controlmodule 8 can be implemented as a PEPS electronic control unit (ECU). ThePEPS control module 8 can communicate with the plurality of sensors 10using a vehicle interface 12. The vehicle interface 12, for example, caninclude a controller area network (CAN) bus and/or a lower data ratecommunication bus, such as a local interconnect network (LIN) bus. Thevehicle interface 12 can also include a clock extension peripheralinterface (CXPI) bus. Additionally or alternatively, the vehicleinterface 12 can include a combination of CAN bus, LIN, and CXPI buscommunication interfaces.

The PEPS control module 8 can locate a portable device 20 by measuringsome aspect of the wireless communication signals between the portabledevice 20 and the sensors 10 of the vehicle 5. For example, the PEPScontrol module 8 can measure the received signal strengths of thecommunication signals between the portable device 20 and the varioussensors 10. In such case, the PEPS control module 8 can determine thelocation of the portable device 20 based on, for example, the patternsof the received signal strength indicator (RSSI) for the various signalssent and received between the portable device 20 and the sensors 10 ofthe vehicle 5. For example, a relatively strong RSSI generally indicatesthat the communicating devices are closer and a relatively weak RSSIgenerally indicates that the communicating devices are farther away. Byanalyzing the RSSI for communication signals sent between the portabledevice 20 and each of the sensors 10, the PEPS control module 8 and/orthe portable device 20 itself can determine a location of the portabledevice 20 relative to the vehicle 5. Additionally or alternatively,angle of arrival or time difference of arrival measurements for thesignals sent and received between the sensors 10 and the portable device20 can also be used by the PEPS control module 8 to determine thelocation of the portable device 20.

Consumer grade wireless protocols employing FHSS communication, such asBluetooth and/or Bluetooth Low Energy (BLE), for example, typicallyoperate within the 2,400 to 2483.5 MHz band to use at least 15 channelsand must not occupy any particular for more than 0.4 seconds, asrequired by the Federal Communications Commission regulation 47 C.F.R.15.247(a)(1)(iii). As noted above, Bluetooth and BLE use FHSS. Wi-fi andWi-fi direct can use DSSS and/or OFDM.

The portable device 20 can include a communication chipset 22, such as aBLE chipset, a Wi-Fi chipset, or a Wi-Fi direct chipset, connected to anantenna 23. The portable device 20 can also include application softwarestored in a computer-readable storage module or device 24. The portabledevice 20 can also optionally include a GPS module 26 or other devicelocation service. The portable device 20 sends and receivescommunication signals 30 to and from the sensors 10.

With reference to FIG. 3, each of the sensors 10 includes acommunication chipset 14, such as a BLE chipset, a Wi-Fi chipset, or aWi-Fi direct chipset, connected to an antenna 15. As shown in FIG. 3,the antenna 15 may be located internal to the sensor 10. Alternatively,the antenna 15 may be located external to the sensors 10. The sensors 10receive communication signals from the portable device 20 using theantenna 15. In the example of FIG. 3, the sensor 10 is configured with aBLE chipset for BLE communication. In the example of FIG. 3, the sensor10 receives BLE physical layer messages using a BLE physical layer (PHY)controller 16. The sensor 10 is capable of observing BLE physical layermessages and taking measurements of the physical properties of theassociated signals, including, for example, the received signal strength(RSSI) using a channel map that is produced by a channel mapreconstruction module 17. Additionally or alternatively, the sensor 10can determine other measurements of the physical properties of theassociated signals, including, for example, data related to the angle ofarrival. Additionally or alternatively, the various sensors 10 cancommunicate with each other and/or communicate with the PEPS controlmodule 8 via the vehicle interface 12 to determine time difference ofarrival, time of arrival, or angle of arrival data for signals receivedby the various sensors. A timing synchronization module 18 is configuredto accurately measure the reception times of messages on the vehicleinterface 12 and pass the timing information to the communicationchipset 14. The communication chipset is configured to take the channelmap information and the timing signals and tune the PHY controller 16 toa specific channel at a specific time and observe all physical layermessages and data that conform to the physical layer specification forthe communication protocol being used. The data, timestamps, andmeasured signal strength are reported by the communication chipset 14 tothe PEPS control module 8 of the vehicle 5 via the vehicle Interface 12.

In addition to the sensors 10, as discussed in further detail below, thePEPS control module 8 may have a separate communication module thatincludes a communication chipset 14, such as a BLE chipset, a Wi-Fichipset, or a Wi-Fi direct chipset, connected to an antenna 15 fordirect communication with the portable device 20, similar to the sensor10 shown in FIG. 3. The communication module of the PEPS control module8 can be configured for BLE communication, for example, and can receiveBLE physical layer messages using a BLE physical layer (PHY) controller16. Additionally or alternatively, the communication module can beconfigured for Wi-Fi or Wi-Fi direct communication. The communicationmodule of the PEPS control module 8 can communicate directly with theportable device 20 and can provide, for example, communicationinformation, such as synchronization and timing information, to theportable device, as discussed in detail below. Similar to the sensor 10shown in FIG. 3, the communication module of the PEPS control module 8can include a timing synchronization module 18 configured to accuratelymeasure the reception times of messages on the vehicle interface 12 andpass the timing information to the BLE chipset. The communicationchipset is configured to take the channel map information and the timingsignals and tune the PHY controller 16 to a specific channel at aspecific time and observe all physical layer messages and data thatconform to the physical layer specification of the communicationprotocol being used.

With reference to FIG. 4, a timing diagram is shown for an exampleimplementation of a PEPS system 1 using a communication protocol thatuses both open and secure connection channels, such as BLE, Wi-Fi, orWi-Fi direct. In the example implementation of FIG. 4, the portabledevice 20 (indicated as PD) communicates with the sensors 10A to 10Fover the available open advertising channels of the communicationprotocol. In this way, in the example implementation of FIG. 4, whileusing a communication protocol that allows for communication over secureconnection channels, the PEPS system 1 actually avoids communicationover the secure connection channels and communicates only over the openadvertising channels that do not require particular communicationinformation, such as timing, synchronization, encryption, etc.,information.

In FIG. 4, the passage of time is indicated from left to right, anadvertising broadcast signal is indicated by an arrow (designated as 40at the bottom of the figure), and a scanning/listening window isindicated by a raised interval (designated as 42 at the bottom of thefigure). The time line is incremented with an indicated time period of 1to 12 for purposes of illustration.

In the example of FIG. 4, the portable device 20 scans/listens for abroadcast signal at scanning/listening windows that are centered on eachof the time intervals 1 to 12, while one of the sensors 10A to 10Ftransmits an advertising broadcast signal during each time interval. Forexample, at each of the time intervals, the portable device 20 beginsscanning/listening just before the time interval and continuesscanning/listening until just after the time interval. In this way, thescanning/listening windows extend for a period of time centered on eachof the time intervals. For example, sensor 10A transmits a broadcastsignal at time intervals 1 and 7. Sensor 10B transmits a broadcastsignal at time intervals 2 and 8. Sensor 10C transmits a broadcastsignal at time intervals 3 and 9. Sensor 10D transmits a broadcastsignal at time intervals 4 and 10. Sensor 10E transmits a broadcastsignal at time intervals 5 and 11. Sensor 10F transmits a broadcastsignal at time intervals 6 and 12.

The portable device 20 can measure one or more aspects of the broadcastsignals transmitted by each of the sensors 10A to 10E. For example, theportable device 20 can measure RSSI, angle of arrival, and/or timedifference of arrival. The portable device 20 can then communicate themeasured data, along with data included in the advertising broadcastsignals and time stamps for the received signals to the PEPS system 1.For example, the portable device 20 can communicate data, time stamps,and the measured data to the PEPS control module 8 through one of thesensors 10A to 10F or through a dedicated central communication moduleof the PEPS control module 8. The PEPS control module 8 can thendetermine the location of the portable device based on the communicatedinformation from the portable device 20. Alternatively, the portabledevice 20 itself can process the data, time stamps, and measured data,such as RSSI, angle of arrival, and/or time difference of arrival, todetermine its location relative to the vehicle 5 and can communicate itslocation to the PEPS control module 8 of the PEPS system 1 eitherthrough one of the sensors 10 or through the communication module of thePEPS control module 8.

Based on the determined location of the portable device 20, the PEPSsystem 1 can then authorize or perform a vehicle function, such asunlocking a door of the vehicle 5, unlocking a trunk of the vehicle 5,starting the vehicle, and/or allowing the vehicle to be started, basedon the location of the portable device 20.

In the example implementation of FIG. 4, optimally the portable device20 and the sensors 10A to 10F can be synchronized so that the broadcasttransmissions of the sensors 10A to 10F line up and coincide with thescanning/listening windows of the portable device 20. To performsynchronization, one of the broadcast transmissions from the sensors 10Ato 10F can include synchronization information regarding the timing ofthe broadcast transmissions, such as the timing interval, the nexttransmit time, etc. In such case, the portable device 20 can start aninitial scanning/listening window at a first time period, and, if itdoes not receive a broadcast transmission, can then adjust the timing ofthe next scanning/listening window by a predetermined or calculatedoffset. The portable device 20 can continue to scan/listen and thenadjust the next scanning/listening window by the predetermined orcalculated offset until it receives a broadcast transmission. Once itreceives an initial broadcast transmission from one of the sensors 10Ato 10F, the portable device 20 can then adjust the timing for itsscanning/listening windows to match the timing of the broadcasttransmissions from the sensors 10A to 10F. Alternatively, a centralcommunication module of the PEPS control module 8 can be used tocommunicate with the portable device 20 and provide the portable device20 with the timing and packet transmission information, such as thetiming interval and the next transmit time. For example, a communicationmodule of the PEPS control module 8 can provide the timing interval andnext transmit time information to the portable device 20. Once received,the portable device 20 can start its next scanning/listening window atthe appropriate time to receive the next broadcast transmission from oneof the sensors 10A to 10F.

In this way, in the example of FIG. 4, it is only necessary for theportable device 20 to scan/listen for broadcast signals transmitted fromthe sensors during the applicable scanning/listening windows, shown ateach of time intervals 1 to 12 in FIG. 4. As such, it is not necessaryfor the portable device 20 to scan/listen for the broadcast signals allof the time. In this way, the portable device can conserve power duringthe periods of time between the scanning/listening windows. In this way,the portable device 20 in the example implementation of FIG. 4 is morepower efficient than a comparable portable device that would otherwisebe required to scan/listen all of the time for advertising broadcastsignals transmitted from sensors of the vehicle. In this way, theexample implementation of FIG. 4 provides the technical benefits ofconserving power of the portable device 20 by only scanning/listeningfor advertising broadcast signals during the appropriate time intervals.

With reference to FIG. 5, a timing diagram is shown for another exampleimplementation of a PEPS system 1 using a communication protocol withboth open and secure connection channels. The example implementation ofFIG. 5 is similar to the example implementation of FIG. 4 in that theportable device 20 (indicated as PD) communicates with the sensors 10Ato 10F only over the available open advertising channels. In this way,in the example implementation of FIG. 5, while using a communicationprotocol that allows for secure connection communications, the PEPSsystem 1 actually avoids communication over secure connections and onlycommunicates over the open advertising channels that do not requirefrequency hopping. In the example of FIG. 5, however, instead of thesensors 10A to 10F transmitting the advertising broadcast signals, theportable device 20 periodically transmits the advertising broadcastsignals while the sensors 10A to 10F scan/listen for the transmittedbroadcast signals from the portable device 20.

Similar to FIG. 4, in FIG. 5 the passage of time is indicated from leftto right, an advertising broadcast signal is indicated by an arrow(designated as 40 at the bottom of the figure), and a scanning/listeningwindow is indicated by a raised interval (designated as 42 at the bottomof the figure).

In the example of FIG. 5, the portable device 20 transmits a broadcastsignal at each time interval while each of the sensors 10A to 10Fscan/listen for the broadcast signal at each interval. In the example ofFIG. 5, the sensors 10 scan/listen for a broadcast signal atscanning/listening windows that are centered on each of the timeintervals 1 to 6, while the portable device 20 transmits a broadcastsignal during each time interval. For example, at each of the timeintervals, the sensors 10 begin scanning/listening just before the timeinterval and continue scanning/listening until just after the timeinterval. In this way, the scanning/listening windows extend for aperiod of time centered on each of the time intervals.

In the example of FIG. 5, the sensors 10A to 10F can each measure one ormore aspects of the broadcast signals transmitted by the portable device20. For example, the sensors 10 can measure RSSI, angle of arrival,and/or time difference of arrival. The sensors 10 can then communicatethe measured data, along with data included in the broadcast signals andtime stamps for the received signals to the PEPS system 1. For example,the sensors 10 can communicate data, time stamps, and the measured datato the PEPS control module 8 through the vehicle interface 12. The PEPScontrol module 8 can then determine the location of the portable devicebased on the communicated information from the sensors 10.

Based on the determined location of the portable device 20, the PEPSsystem 1 can then authorize or perform a vehicle function, such asunlocking a door of the vehicle 5, unlocking a trunk of the vehicle 5,starting the vehicle, and/or allowing the vehicle to be started, basedon the location of the portable device 20.

In the example implementation of FIG. 5, similar to the exampleimplementation of FIG. 4, optimally the portable device 20 and thesensors 10A to 10F are synchronized so that the broadcast transmissionsof the portable device line up or coincide with the scanning/listeningwindows of the sensors 10A to 10F. For example, one of the broadcasttransmissions from the portable device 20 can include synchronizationinformation regarding the timing of the broadcast transmissions, such asthe timing interval, the next transmit time, etc. In such case, one ormore of the sensors 10 can start an initial scanning/listening window ata first time period, and, if a broadcast transmission is not received,the timing of the next scanning/listening window can be adjusted by apredetermined or calculated offset. The one or more sensors 10 cancontinue to scan/listen and then adjust the next scanning/listeningwindow by the predetermined or calculated offset until a broadcasttransmission is received. Once an initial broadcast transmission isreceived from the portable device 20, the sensors 10A to 10F cancommunicate with each other to adjust the timing for thescanning/listening windows to match the timing of the broadcasttransmissions from the portable device 20. Alternatively, acommunication module of the PEPS control module 8 in the vehicle 5 canbe used to communicate and synchronize the timing and packettransmission information, such as the timing interval and the nexttransmit time, so that the scan/listening windows of the sensors 10 lineup or coincide with the broadcast transmission of the portable device20. For example, the communication module of the PEPS control module 8can receive the timing interval and next transmit time information fromthe portable device 20. Once received, the PEPS control module 8 cancommunicate the timing interval and next transmit time information tothe sensors 10, which can then start their next scanning listeningwindows at the appropriate time to receive the next broadcasttransmission from the portable device 20.

In this way, in the example of FIG. 5, it is only necessary for thesensors 10 to scan/listen for broadcast signals transmitted from theportable device 20 during the applicable scanning/listening windows,shown at each of time intervals 1 to 6 in FIG. 4. As such, it is notnecessary for the sensors 10 to scan/listen for the broadcast signalsall of the time. In this way, the vehicle 5 can conserve power duringthe periods of time between the scanning/listening windows. In this way,the sensors 10 and the vehicle 5 in the example implementation of FIG. 4is more power efficient than a comparable system that would otherwise berequired to scan/listen all of the time for broadcast signalstransmitted from a portable device. In this way, the exampleimplementation of FIG. 5 provides the technical benefits of conservingpower of the sensors 10 and/or the vehicle 5 by only scanning/listeningfor broadcast signals during the appropriate time intervals.

With reference to FIGS. 6 and 7, another example implementation isshown. In the example implementation of FIGS. 6 and 7, instead ofcommunicating over the open advertising channels, the portable device 20establishes individual secure connections with each of the sensors 10using the secure connection channels of the communication protocol, suchas BLE, Wi-Fi, or Wi-Fi direct. In this example implementation, theportable device 20 serves as the central device or master andestablishes individual secure connections with each individual sensor10A to 10F serving as a peripheral device or slave, as shown in FIG. 6.In this way, a private area network (PAN) star topology is establishedwith the portable device serving as the central device or master andeach of the sensors serving as a peripheral device or slave. In thisexample implementation, the communication links between the portabledevice 20 and each of the sensors 10 can utilize communication protocolsusing FHSS, DSSS, and/or OFDM, such as Bluetooth, Wi-Fi, and/or Wi-Fidirect, and/or can utilize encrypted communication packets. As such,communication between the portable device 20 and each of the sensors 10is private, secure, and difficult to intercept or track by a third-partyor unauthorized device.

With reference to FIG. 7, a timing diagram is shown for the exampleimplementation of FIG. 6, using a communication protocol with both openand secure connection channels, such as BLE, Wi-Fi, or Wi-Fi direct. Asnoted above, unlike the example implementations of FIGS. 4 and 5, in theexample implementation of FIGS. 6 and 7, the portable device 20establishes individual secure communication links with each of thesensors. As such, the portable device 20 establishes individualcommunication windows for each of the sensors, labelled “10A Comm.,”“10B Comm.,” “10C Comm.,” “10D Comm.,” “10E Comm.,” and “10F Comm.” inFIG. 7, with the passage of time proceeding from left to right in thefigure. In each of the communication windows, the portable device 20communicates using a secure connection with each respective sensor. Forexample, the portable device 20 communicates with sensor 10A usingsecure connection 43A, with sensor 10B using secure connection 43B, withsensor 10C using secure connection 43C, with sensor 10D using secureconnection 43D, with sensor 10E using secure connection 43E, and withsensor 10F using secure connection 43F. The secure connections 43A to43F are generically referred to as secure connections 43 or secureconnection 43. During each secure connection 43, the portable device andthe respective sensor 10 can communicate with the master device, in thiscase the portable device 20 transmitting an initial communication packetand the slave device, in this case the sensor 10, sending a responsecommunication packet. While one initial communication from the portabledevice 20 and one response communication from the sensor 10 is shown ineach secure connection 43 of FIG. 7, multiple rounds of communicationpackets can be sent back and forth between the portable device 20 andthe sensor 10 during each secure connection event. In other words, asecure connection event could have multiple iterations of an initialcommunication packet sent from the master device to the slave device andof the response communication packet from the slave device to the masterdevice, with multiple communication messages sent and received betweenthe portable device 20 and the sensor 10 during a single connectionevent and communication window, in accordance with the specifications ofthe particular communication protocol being used. The same is true forthe secure connections (e.g., 43A-1, 43A-2, 43A-3, and 43A-4)illustrated in FIGS. 8 to 11, which are discussed in further detailbelow.

Further, in accordance with the specifications of the particularcommunication protocol being used, the portable device 20 coordinatesand synchronizes the communication with each individual sensor 10 sothat each sensor knows the timing and the particular channel to use forthe next communication. For example, if an FHSS communication protocolis being used, the portable device 20 coordinates the communication witheach sensor 10 so that both devices know the channel or frequency to usefor the next communication and the timing for when that communicationshould occur. Because the portable device 20 establishes individualsecure communication links with each of the sensors 10, it mustcoordinate the timing and frequency hopping for each of the individualsecure communication links and communicate the appropriate timing andsynchronization information to each of the individual sensors 10.

The portable device 20 can measure one or more aspects of the signalstransmitted by each of the sensors 10A to 10E during each communicationwindow. For example, the portable device 20 can measure RSSI, angle ofarrival, and/or time difference of arrival. The portable device 20 canthen communicate the measured data, along with data included in thebroadcast signals and time stamps for the received signals to the PEPSsystem 1. For example, the portable device 20 can communicate data, timestamps, and the measured data to the PEPS control module 8 through oneof the sensors 10A to 10F or through a dedicated central communicationmodule of the PEPS control module 8. The PEPS control module 8 can thendetermine the location of the portable device 20 based on thecommunicated information from the portable device 20. Alternatively, theportable device 20 itself can process the data, time stamps, andmeasured data, such as RSSI, angle of arrival, and/or time difference ofarrival, to determine its location relative to the vehicle 5 and cancommunicate its location to the PEPS control module 8 of the PEPS system1 either through one of the sensors 10 or through the communicationmodule of the PEPS control module 8. Additionally or alternatively, thesensors 10 can measure RSSI, angle of arrival, and/or time difference ofarrival for the communication signals sent and received between theportable device 20 and the sensors 10 and can communicate the measureddata to the PEPS control module 8 over the vehicle interface 12. ThePEPS control module 8 can then determine the location of the portabledevice 20 based on the communicated information from the sensors 10.

Based on the determined location of the portable device 20, the PEPSsystem 1 can then authorize or perform a vehicle function, such asunlocking a door of the vehicle 5, unlocking a trunk of the vehicle 5,starting the vehicle, and/or allowing the vehicle to be started, basedon the location of the portable device 20.

With reference to FIGS. 8-11, timing diagrams are shown for additionalexample implementations of PEPS systems 1 using a communication protocolwith both open and secure connection channels, such as BLE, Wi-Fi, orWi-Fi direct. While the example implementations of FIGS. 4 and 5utilized communication only over the available open advertising channelsand while the example implementation of FIGS. 6 and 7 utilizedcommunication only over secure communication connections, the exampleimplementations of FIGS. 8-11 provide mixed mode implementations thatperform communication using the both the available open advertisingchannels and the secure communication. For example, in each of theexample implementations of FIGS. 8-11 a secure communication connectionis established between the portable device 20 and one of the sensors 10.As noted above, unlike communication over the open advertising channels,communication over the secure communication connections is performedwith using FHSS, DSSS, and/or OFDM, such as in secure communicationconnections using Bluetooth, Wi-Fi, and/or Wi-Fi direct. Additionally oralternatively, communication over the secure communication connectionscan utilize encrypted communication packets. As such, the exampleimplementations of FIG. 8-11 provide a PEPS system 1 that cancommunicate with the portable device 20 securely using communicationpackets sent over the secure communication connections, while stillallowing for communication between the portable device 20 and theremaining sensors over the open advertising channels.

With reference to FIG. 8, a timing diagram is shown for an exampleimplementation of a PEPS system 1 using a communication protocol withboth open and secure connection channels, such as BLE, Wi-Fi, or Wi-Fidirect, and including communication packets being sent over both theopen advertising channels and over secure communication connections43A-1 and 43A-2. In the example implementation of FIG. 8, the portabledevice 20 (designated as PD) establishes a secure connection with one ofthe sensors 10. Specifically, in the example of FIG. 8, the portabledevice 20 establishes a secure connection with sensor 10A. While sensor10A is used as an example, the portable device 20 could insteadestablish a secure connection with any of the sensors 10B to 10F.Additionally or alternatively, the vehicle 5 could include an additionalcommunication node dedicated to performing communication over a securecommunication connection with the portable device 20. For example,portable device 20 could establish a secure communication connectionwith the central communication module of the PEPS control module 8.

In the example implementation of FIG. 8, sensor 10A serves as the masterand the portable device 20 serves as the slave for the securecommunication connections 43A-1, 43A-2. Further, similar to the abovetiming diagrams, the passage of time is indicated as proceeding fromleft to right. As shown in FIG. 8, the example implementation includes afirst time period 80 for communication over a secure communicationconnection 43A-1 between the portable device 20 and the master nodesensor 10A. During the first time period 80, communications areperformed between the portable device 20 and the master node sensor 10A,as shown by the secure communication connection designated by block43A-1. As noted above, while a single transmission and response pair isshown in the secure communication connection 43A-1, multipletransmission and response pairs could occur between the portable device20 and the master node sensor 10A during the secure communicationconnection event.

The first time period 80 is followed by a second time period 82, duringwhich communications are performed between the portable device 20 andone or more of the other sensors 10B to 10F over the open advertisingchannels. As noted above, communication over the open advertisingchannels is not encrypted and does not use frequency hopping. As shownin FIG. 8, during the second time period 82, the portable device 20transmits broadcast signals 44 during the second time period 82. While asingle broadcast signal 44 is shown in the example of FIG. 8 forillustration, the portable device 20 can transmit any number ofbroadcast signals 44, depending on the length of the second time period82, the number of sensors 10 communicating over the open advertisingchannels, etc. As further shown in FIG. 8, sensors 10B to 10F eachperform scanning/listening for the transmitted broadcast signals 44during designated scanning/listening windows 42. Again, while a singlescanning/listening window 42 is shown for each sensor 10 in FIG. 8, anynumber of scanning/listening windows 42 can be used, depending on thelength of the second time period 82, the number of sensors 10communicating over the open advertising channels, etc.

The timing for the communication between the portable device 20 andsensors 10B to 10F can be synchronized and coordinated by, for example,the PEPS control module 8 based on communication with the portabledevice 20 over the secure communication connection 43A-1 during timeperiod 80. For example, sensor 10A can communicate with the portabledevice 20 over the secure communication connection 43A-1 and with thePEPS control module 8 over the vehicle interface 12. Once the portabledevice 20 and the PEPS control module 8 establish the timing for thecommunication over the open advertising channels, the PEPS controlmodule 8 can inform sensors 10B to 10F of the timing so that the sensors10B to 10F can synchronize their respective scanning/listening windows42 accordingly. For example, the portable device 20 could transmit thebroadcast signals 44 at predetermined intervals such as, for example 10ms. The portable device 20 could inform the PEPS control module 8 of thetiming for the first (or next) broadcast signal 44 via communicationwith sensor 10A over the secure communication connection 43A-1. The PEPScontrol module 8 can then inform sensors 10B to 10F of the time for thefirst (or next) broadcast signal and can inform the sensors of thetiming interval between broadcast signals such as, for example, 10 ms.The sensors 10B to 10F can then synchronize their scanning/listeningwindows 42 to bracket the anticipated time for the next broadcastsignal. For example, if the next broadcast signal 44 is scheduled for ata time of 10 ms, the scanning/listening windows 42 could start at 8 msand continue until 12 ms to insure the scanning/listening window 42 isactive when the broadcast signal 44 is transmitted.

The second time period 82 is followed by a third time period 84, duringwhich the portable device 20 and sensor 10A return to communicating oversecure communication connection 43A-2.

In the example of FIG. 8, the sensors 10A to 10F can each measure one ormore aspects of the signals transmitted by the portable device 20. Forexample, sensor 10A can measure aspects of the signals transmittedduring the secure connection communications, shown in blocks 43 andsensors 10B to 10F can measure aspects of the broadcast signals 44transmitted by the portable device 20 over the open communicationchannels. For example, the sensors 10 can measure RSSI, angle ofarrival, and/or time difference of arrival. The sensors 10 can thencommunicate the measured data, along with data included in the receivedsignals and time stamps for the received signals to the PEPS system 1.For example, the sensors 10 can communicate data, time stamps, and themeasured data to the PEPS control module 8 through the vehicle interface12. The PEPS control module 8 can then determine the location of theportable device based on the communicated information from the sensors10.

Based on the determined location of the portable device 20, the PEPSsystem 1 can then authorize or perform a vehicle function, such asunlocking a door of the vehicle 5, unlocking a trunk of the vehicle 5,starting the vehicle, and/or allowing the vehicle to be started, basedon the location of the portable device 20.

With reference to FIG. 9, a timing diagram is shown for another exampleimplementation of a PEPS system 1 using a communication protocol withboth open and secure connection channels, such as BLE, Wi-Fi, or Wi-Fidirect, and including communication packets being sent over both theopen advertising channels and over secure communication connections43A-1 and 43A-2. The example implementation of FIG. 9 is similar to theexample implementation of FIG. 8 except that in the exampleimplementation of FIG. 9, sensors 10B to 10F send broadcast signals 40Bto 40F, respectively, over the open advertising channels during thesecond time period 82 and the portable device 20 scans/listens for thebroadcast signals 40B to 40F during the scanning/listening windows 42 ofthe second time period 82. Similar to the example implementation of FIG.8, in the example implementation of FIG. 9, the portable device 20(designated as PD) establishes a secure connection with one of thesensors 10. Specifically, in the example of FIG. 9, the portable device20 establishes a secure connection with sensor 10A. While sensor 10A isused as an example, the portable device 20 could instead establish asecure connection with any of the sensors 10B to 10F. Additionally oralternatively, the vehicle 5 could include an additional communicationnode dedicated to performing communication over a secure communicationconnection with the portable device 20. For example, portable device 20could establish a secure communication connection the centralcommunication module of the PEPS control module 8.

In the example implementation of FIG. 9, sensor 10A serves as the masterand the portable device 20 serves as the slave for the securecommunication connection. Further, similar to the above timing diagrams,the passage of time is indicated as proceeding from left to right. Asshown in FIG. 9, the example implementation includes a first time period80 for communication over secure communication connection 43A-1 betweenthe portable device 20 and the master node sensor 10A. During the firsttime period 80, secure connection communications are performed betweenthe portable device 20 and the master node sensor 10A, as shown by thecommunications designated by block 43A-1. As noted above, while a singletransmission and response pair is shown in the secure communicationconnection 43A-1, multiple transmission and response pairs could occurbetween the portable device 20 and the master node sensor 10A during thesecure communication connection event.

The first time period 80 is followed by a second time period 82, duringwhich communications are performed between the portable device 20 andone or more of the other sensors 10B to 10F over the open advertisingchannels. As noted above, communication over the open advertisingchannels is not encrypted and does not use FHSS, DSSS, and/or OFDM. Asshown in FIG. 9, during the second time period 82, sensors 40B to 40Ftransmit broadcast signals 40B to 40F, respectively, during the secondtime period 82. While five broadcast signals 40B to 40F are shown in theexample of FIG. 9 for illustration, the sensors 10B to 10F can transmitany number of broadcast signals, depending on the length of the secondtime period 82, the total number of sensors 10 communicating over theopen advertising channels, etc. As further shown in FIG. 9, the portabledevice 20 performs scanning/listening for the transmitted broadcastsignals 40B to 40F during designated scanning/listening windows 42.Again, while five scanning/listening windows 42 are shown in FIG. 9, anynumber of scanning/listening windows 42 can be used, depending on thelength of the second time period 82, the number of sensors 10communicating over the open advertising channels, etc.

The timing for the communication between the portable device 20 andsensors 10B to 10F during the second time period 82 can be synchronizedand coordinated by, for example, the PEPS control module 8 based oncommunication with the portable device 20 over the secure connectionduring the first time period 80. For example, sensor 10A can communicatewith the portable device 20 over the secure connection and with the PEPScontrol module 8 over the vehicle interface 12. Once the portable device20 and the PEPS control module 8 establish the timing for thecommunication over the open advertising channels, the PEPS controlmodule 8 can inform sensors 10B to 10F of the timing so that the sensors10B to 10F can synchronize the broadcast signals 40B to 40F with therespective scanning/listening windows 42 of the portable device 20. Forexample, the sensors 10B to 10F can transmit the broadcast signals 40Bto 40F at predetermined intervals such as, for example 10 ms. Thesensors 10B to 10F can inform the PEPS control module 8 of the timingfor the first (or next) broadcast signal 44 via communication with thevehicle interface 12. The PEPS control module 8 can then communicate thetiming information to sensor 10A to communicate to the portable device20 over the secure communication connection during the first time period80. In this way, the PEPS control module 8 can inform the portabledevice 20 of the time for the first (or next) broadcast signal and caninform the portable device 20 of the timing interval between broadcastsignals such as, for example, 10 ms. The portable device 20 can thensynchronize its scanning/listening windows 42 to bracket the anticipatedtime for the next broadcast signal. For example, if the next broadcastsignal 40B is scheduled for a time of 10 ms, the correspondingscanning/listening windows 42 can start at 8 ms and continue until 12 msto insure the scanning/listening window 42 is active when the broadcastsignal 40B is transmitted.

The second time period 82 is followed by a third time period 84, duringwhich the portable device 20 and sensor 10A return to communicating overthe secure connection, as shown by block 43A-1.

In the example of FIG. 9, the portable device 20 can measure one or moreaspects of the signals transmitted by the sensors 10. For example, theportable device 20 can measure aspects of the signals transmitted bysensor 10A during the secure connection communications, shown in blocks43A-1. In addition, the portable device 20 can measure aspects of thebroadcast signals 40B to 40F transmitted by the sensors 10B to 10F overthe open communication channels. For example, the portable device canmeasure RSSI, angle of arrival, and/or time difference of arrival. Theportable device 20 can then communicate the measured data, along withdata included in the received signals and time stamps for the receivedsignals to the PEPS system 1. For example, the portable device 20 cancommunicate data, time stamps, and the measured data to the PEPS controlmodule 8 through communication with one or more of the sensors 10A to10F. The sensors 10 can, for example, communicate the information to thePEPS control module 8 via communication over the vehicle interface 12.The PEPS control module 8 can then determine the location of theportable device based on the communicated information from the sensors10.

Based on the determined location of the portable device 20, the PEPSsystem 1 can then authorize or perform a vehicle function, such asunlocking a door of the vehicle 5, unlocking a trunk of the vehicle 5,starting the vehicle, and/or allowing the vehicle to be started, basedon the location of the portable device 20.

With reference to FIG. 10, a timing diagram is shown for another exampleimplementation of a PEPS system 1 using a communication protocol withboth open and secure connection channels, such as BLE, Wi-Fi, or Wi-Fidirect, and including communication packets being sent over both theopen advertising channels and over secure communication connections43A-3 and 43A-4. The example implementation of FIG. 10 is similar to theexample implementation of FIG. 8 except that in the exampleimplementation of FIG. 10 the portable device 20 serves as the masterand sensor 10A serves as the slave during the secure connectioncommunications shown by blocks 43A-3 and 43A-4. In all other respects,the example implementation of FIG. 10 operates the same as the exampleimplementation of FIG. 8, the discussion of which is not repeated here.

With reference to FIG. 11, a timing diagram is shown for another exampleimplementation of a PEPS system 1 using a communication protocol withboth open and secure connection channels, such as BLE, Wi-Fi, or Wi-Fidirect, and including communication packets being sent over both theopen advertising channels and over secure communication connections43A-3 and 43A-4. The example implementation of FIG. 11 is similar to theexample implementation of FIG. 9 except that in the exampleimplementation of FIG. 11 the portable device 20 serves as the masterand sensor 10A serves as the slave during the secure connectioncommunications shown by blocks 43. In all other respects, the exampleimplementation of FIG. 11 operates the same as the exampleimplementation of FIG. 9, the discussion of which is not repeated here.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

In this application, including the definitions below, the terms “module”and “system” may refer to, be part of, or include circuits or circuitrythat may include processor hardware (shared, dedicated, or group) thatexecutes code and memory hardware (shared, dedicated, or group) thatstores code executed by the processor hardware. The code is configuredto provide the features of the modules and systems described herein. Inaddition, in this application the terms “module” and “system” may bereplaced with the term “circuit.” The term “memory hardware” may be asubset of the term computer-readable medium. The term computer-readablemedium does not encompass transitory electrical and electromagneticsignals propagating through a medium, and may therefore be consideredtangible and non-transitory. Non-limiting examples of a non-transitorytangible computer readable medium include nonvolatile memory, volatilememory, magnetic storage, and optical storage.

The apparatuses and methods described in this application may bepartially or fully implemented by a special purpose computer created byconfiguring a general purpose computer to execute one or more particularfunctions embodied in computer programs. The functional blocks,flowchart components, and other elements described above serve assoftware specifications, which can be translated into the computerprograms by the routine work of a skilled technician or programmer.

The computer programs include processor-executable instructions that arestored on at least one non-transitory, tangible computer-readablemedium. The computer programs may also include or rely on stored data.The computer programs may encompass a basic input/output system (BIOS)that interacts with hardware of the special purpose computer, devicedrivers that interact with particular devices of the special purposecomputer, one or more operating systems, user applications, backgroundservices, background applications, etc.

The computer programs may include: (i) descriptive text to be parsed,such as JavaScript Object Notation (JSON), hypertext markup language(HTML) or extensible markup language (XML); (ii) assembly code; (iii)object code generated from source code by a compiler; (iv) source codefor execution by an interpreter; (v) source code for compilation andexecution by a just-in-time compiler, etc. As examples only, source codemay be written using syntax from languages including C, C++, C #,Objective C, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal,Curl, OCaml, Javascript®, HTML5, Ada, ASP (active server pages), PHP,Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, andPython®.

None of the elements recited in the claims are intended to be ameans-plus-function element within the meaning of 35 U.S.C. § 112(f)unless an element is expressly recited using the phrase “means for,” orin the case of a method claim using the phrases “operation for” or “stepfor.”

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

What is claimed is:
 1. A system comprising: a first sensor configuredfor wireless communication with a portable device using a communicationprotocol that allows for communication using a secure communicationconnection and at least one open advertising communication channel, thefirst sensor being configured to communicate with the portable deviceusing the secure communication connection during a first time period anda third time period, the third time period being after the first timeperiod; a plurality of second sensors each configured to transmitbroadcast signals to the portable device over the at least one openadvertising communication channel during a second time period betweenthe first time period and the third time period; and a control moduleconfigured to (i) communicate with the first sensor and the plurality ofsecond sensors, (ii) determine, prior to the second time period, timinginformation for the plurality of second sensors to transmit thebroadcast signals over the at least one open advertising communicationchannel during the second time period, (iii) communicate the timinginformation to the plurality of second sensors, the plurality of secondsensors being configured to transmit the broadcast signals to theportable device over the at least one open advertising communicationchannel during the second time period based on the timing information,(iv) communicate the timing information to the portable device via thefirst sensor using the secure communication connection during the firsttime period, the portable device being configured to establish scanningwindows for receiving the broadcast signals during the second timeperiod based on the timing information, (v) receive first signalinformation about first signals transmitted by the first sensor over thesecure communication connection during the first time period and secondsignal information about the broadcast signals transmitted by theplurality of second sensors during the second time period, the firstsignal information and the second signal information being communicatedfrom the portable device to the control module over the securecommunication connection during the third time period, and (vi)determine a current location of the portable device based on the firstsignal information and the second signal information; wherein the firstsignal information and the second signal information include at leastone of received signal strength indicator information, angle of arrivalinformation, and time difference of arrival information.
 2. The systemof claim 1, wherein the first sensor and the plurality of second sensorsare installed in a vehicle and the control module is further configuredto perform a vehicle function including at least one of unlocking a doorof the vehicle, unlocking a trunk of the vehicle, and allowing thevehicle to be started based on the current location of the portabledevice.
 3. The system of claim 1, wherein the timing informationincludes a broadcast time for a next broadcast signal to be transmittedover the at least one open advertising communication channel during thesecond time period.
 4. The system of claim 1, wherein the timinginformation further includes a timing interval between the broadcastsignals to be transmitted over the at least one open advertisingcommunication channel during the second time period.
 5. The system ofclaim 1, wherein the first sensor is configured to communicate with theportable device using the secure communication connection by performingfrequency hopping spread spectrum communication.
 6. The system of claim1, wherein the first sensor is configured to communicate with theportable device using the secure communication connection by at leastone of sending and receiving encrypted communication packets.
 7. Thesystem of claim 1, wherein the first sensor is configured to communicatewith the portable device using at least one of direct-sequence spreadspectrum communication and orthogonal frequency-division multiplexingcommunication.
 8. The system of claim 1, wherein the first sensor isconfigured to serve as a master and the portable device is configured toserve as a slave for the communication using the secure communicationconnection during the first time period and the third time period. 9.The system of claim 1, wherein the portable device is configured toserve as a master and the first sensor is configured to serve as a slavefor the communication using the secure communication connection duringthe first time period and the third time period.
 10. A methodcomprising: performing, with a first sensor, wireless communication witha portable device using a communication protocol that allows forcommunication using a secure communication connection and at least oneopen advertising communication channel, the first sensor communicatingwith the portable device using the secure communication connectionduring a first time period and a third time period, the third timeperiod being after the first time period; determining, with a controlmodule, timing information for a plurality of second sensors to transmitbroadcast signals to the portable device over the at least one openadvertising communication channel during a second time period betweenthe first time period and the third time period, the control modulebeing in communication with the first sensor and the plurality of secondsensors; communicating, with the control module, the timing informationto the portable device via the first sensor using the securecommunication connection during the first time period, the portabledevice establishing scanning windows for receiving the broadcast signalsduring the second time period based on the timing information;communicating, with the control module, the timing information to theplurality of second sensors; transmitting, with the plurality of secondsensors, the broadcast signals to the portable device over the at leastone open advertising communication channel during the second time periodbased on the timing information; receiving, with the control module,first signal information about first signals transmitted by the firstsensor over the secure communication connection during the first timeperiod and second signal information about the broadcast signalstransmitted by the plurality of second sensors during the second timeperiod, the first signal information and the second signal informationbeing communicated from the portable device to the control module overthe secure communication connection during the third time period; anddetermining, with the control module, a current location of the portabledevice based on the first signal information and the second signalinformation; wherein the first signal information and the second signalinformation include at least one of received signal strength indicatorinformation, angle of arrival information, and time difference ofarrival information.
 11. The method of claim 10, wherein the firstsensor and the plurality of second sensors are installed in a vehicle,the method further comprising performing, with the control module, avehicle function including at least one of unlocking a door of thevehicle, unlocking a trunk of the vehicle, and allowing the vehicle tobe started based on the current location of the portable device.
 12. Themethod of claim 10, wherein the timing information includes a broadcasttime for a next broadcast signal to be transmitted over the at least oneopen advertising communication channel during the second time period.13. The method of claim 10, wherein the timing information furtherincludes a timing interval between the broadcast signals to betransmitted over the at least one open advertising communication channelduring the second time period.
 14. The method of claim 10, wherein thefirst sensor communicates with the portable device using the securecommunication connection by performing frequency hopping spread spectrumcommunication.
 15. The method of claim 10, wherein the first sensorcommunicates with the portable device using the secure communicationconnection by at least one of sending and receiving encryptedcommunication packets.
 16. The method of claim 10, wherein the firstsensor communicates with the portable device using at least one ofdirect-sequence spread spectrum communication and orthogonalfrequency-division multiplexing communication.
 17. The method of claim10, wherein the first sensor serves as a master and the portable deviceserves as a slave for while communicating using the secure communicationconnection during the first time period and the third time period. 18.The method of claim 10, wherein the portable device serves as a masterand the first sensor serves as a slave for while communicating using thesecure communication connection during the first time period and thethird time period.
 19. A system comprising: a control module configuredfor communication with a first sensor and a plurality of second sensors,the first sensor being configured for wireless communication with aportable device using a communication protocol that allows forcommunication using a secure communication connection and at least oneopen advertising communication channel, the first sensor also beingconfigured to communicate with the portable device using the securecommunication connection during a first time period and a third timeperiod, the third time period being after the first time period, and theplurality of second sensors each being configured to transmit broadcastsignals to the portable device over the at least one open advertisingcommunication channel during a second time period between the first timeperiod and the third time period; wherein the control module isconfigured to (i) determine, prior to the second time period, timinginformation for the plurality of second sensors to transmit thebroadcast signals over the at least one open advertising communicationchannel during the second time period, (ii) communicate the timinginformation to the plurality of second sensors, the plurality of secondsensors being configured to transmit the broadcast signals to theportable device over the at least one open advertising communicationchannel during the second time period based on the timing information,(iii) communicate the timing information to the portable device via thefirst sensor using the secure communication connection during the firsttime period, the portable device being configured to establish scanningwindows for receiving the broadcast signals during the second timeperiod based on the timing information, (iv) receive first signalinformation about first signals transmitted by the first sensor over thesecure communication connection during the first time period and secondsignal information about the broadcast signals transmitted by theplurality of second sensors during the second time period, the firstsignal information and the second signal information being communicatedfrom the portable device to the control module over the securecommunication connection during the third time period, and (v) determinea current location of the portable device based on the first signalinformation and the second signal information; and wherein the firstsignal information and the second signal information include at leastone of received signal strength indicator information, angle of arrivalinformation, and time difference of arrival information.
 20. The systemof claim 19, wherein the first sensor and the plurality of secondsensors are configured for installation in a vehicle and the controlmodule is further configured to perform a vehicle function including atleast one of unlocking a door of the vehicle, unlocking a trunk of thevehicle, and allowing the vehicle to be started based on the currentlocation of the portable device.